Ink Jet Printing Frank E. Talke Spring 2008 MAE 268

Transcription

1 Ink Jet Printing Frank E. Talke Spring 2008 MAE 268

2 Outline Review of Print Technology before 1980 Principles of Ink jet technology Continuous ink jet technology Drop on demand ink jet technology Design of drop on demand print head Discussion of HP papers on design and manufacturing of drop on demand print head

3 Print technology in the 1970 s Impact printing Slow Noisy Expensive Not all points addressable

4 Principle of Impact printing back printing Print type paper Print hammer Color ribbon

5 Typical Impact printer

6 Typical impact printer

7 Alternative technologies: impact free printing Laser printing Inkjet printing Continuous ink jet Drop-on-Demand inkjet

8 Continuous ink jet technology continuous Only 3 percent of drops are used High drop rate Ink sump required Ink must be cleaned

9 Continuous ink jet

10 All points addressable print technology

11 Multi nozzle print head

12 Ink jet printer with multi nozzle print head

13 Drop-on on-demand Inkjet Technologie Drop-on-Demand Drop only created if drop is needed Low drop rate Multi nozzle head is needed

14 Drop-on on-demand drop generator

15 Drop generator according to Stemme

16 Drop-on on-demand Principle

17 Drop formation in Drop-on on-demand Inkjet

18 Technical difficulties of drop on demand ink jet technology Formation of gas bubbles Chemistry of ink Small drop rates Fabrication of a cheap and disposable print head Leaking of ink from nozzle

19 Inherent contradiction of ink jet technology Ink shall never dry in the nozzle Ink shall be dry on paper instantaneously

20 Schematic of inkjet print head (Heinzl( Heinzl)

21 PT 80 ink jet print head

22 Nozzle plate Gas bubble heat element ink Principle of thermal ink jet (HP)

23 Thermal ink jet print head

24 nozzles contacts Ink reservoir Typical thermal ink jet head (HP)

25 Typical thermal inkjet head (HP, Cannon)

26 8 Typical color printer

27 Typical ink jet printer (HP)

28 Summary Ink jet printing is interdisciplinary Thermal ink jet head is a very complicated materials/mechanics device Little information on fabrication of print head is available in the open literature In the following, we will discuss the fabrication and materials issues of the HP print head based on publications by HP.

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30 Discussion of HP papers on print head design and principles of color printing Bubble jet (thermal jet) Use of semi-conductor technology for head fabrication Heating of planar resistor creates bubbles which collapse Throw away head (very important) Hp, Cannon, Lexmark, etc. Black and white and color

31 HP print head

32 Schematic of ink jet nozzle

33 Schematic of nozzle and resistor

34 Heater fluid interface

35 Temperature profile in liquid/solid interface

36 Temperature profile in heater and fluid

37 Temperature profile in thermal printer

38 Pulse energy as a function of thickness of passivation layer

39 Drop ejection

40 Simulation of drop ejection

41 Typical ink jet print head (again)

42 Fabrication of ink jet head Nozzle plate is most critical part Resistance heater and nozzle plate must be bonded and assembled with ink cartridge Disposable Refillable Life time considerations cheap

43 Fabrication steps

44 Resistor structure

45 Pinholes cause reliability problems

46 Lifetime vs. type and thickness of passivation layer

47 Passivation micro cracks

48 Next step: Fabrication of orifice plate

49 Layout of orifice plate

50 Nozzle and barrier wall

51 Nozzle plate fabrication Fabrication of nozzle plate is done by electro forming on a mandrel A mandrel has the inverse shape (negative) of the final nozzle plate Fabrication of one mandrel (master) allows replication by electro forming of many nozzle plates Plated parts are removed and the master is reused for repeated nozzle plate fabrication

52 Mandrel fabrication

53 Schematic of electroforming

54 Electroforming of orifice plate

55 Front view of nozzle plate

56 Back view of orifice nozzle plate

57 Print head after assembly (again)

58 Discussion Hi tech part of printer is nozzle plate Laser can also be used for making holes for nozzle Silicon micro mechanics potentially easy but never commercialized Printer does not make money, but the expendables like ink cartridges do.

59 Color drop on demand ink jet print head design using piezoelectric squeeze tubes (Lee, Mills, Talke, IBM Journal 1984)

60 Dod discrete print head drivers

61 Drop velocity vs. pulse width

62 Dod discrete print head drivers

63 Design of color print head (1980)

64 Epson Piezoelectric print head Planar piezoelectric elements Commercially available Not a bubble jet

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67 Color perception Three requirements Light source Object with pigment Observer

68 Human eye

69 Human eye (cont.) Rods -- rhodopsin Night vision

70 Human eye (cont.) Cones -- erythrolabe, chlorolabe and rhodopsin Color vision

71 Perception spectrum

72 Color properties Hue, Saturation, Lightness (Brightness) (HSB)

73 Color properties (cont.) Red, Green, Blue (RGB) Cyan, Magenta, Yellow, Black (CMYK)

74 Object with pigment Subtractive scheme primary colors

75 Additive / Subtractive mixing Computer Monitors, TV s -- Additive Printers, photographs -- Subtractive

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79 Photo Album by Home

80 Summary Color printing has become accepted everywhere Human eye is sensitive only to RGB Additive primaries are complements to subtractive primaries Advances bring high quality printing to the home Without mems technology, there would be no color printing Timing for technology is very important: without fast computers and high storage disks, color printing would not exist